Questions tagged [electronegativity]

Refers to ability for an atom in a covalent framework to attract electron density to itself. Do not conflate with electron affinity, which is the ability of a lone atom (or molecule) to attract an electron to itself. Both are measured in joules/mole.

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Is KF the most ionic compound?

I saw somewhere (can't recall where) that KF is the most ionic compound. I expected CsF. Does the greater polarizability of Cs allow it to more easily form covalent bonds compared to K? Does this ...
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Is HF the least acidic hydrogen halide?

Fluorine is the most electronegative halogen and therefore, there is larger difference in electronegativity between the atoms of $\ce{HF}$ than any other hydrogen halide, which means the positive ...
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Electronegativity Considerations in Assigning Oxidation States

I have never seen anything other than a set of rules like these when textbooks present how to assign oxidation numbers. Such as these: However, if we keep in mind that oxidation numbers are simply ...
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Why is carbon dioxide nonpolar?

I understand that polarity corresponds to an electronegativity difference and that the larger the electronegativity difference, the more polar the bond. However, I have read that carbon dioxide is ...
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What happens if the electronegativity difference is exactly 2.1?

I'm learning about electronegativity in atoms and how their difference affects the type of bond they make. I know that no difference makes a non-polar covalent bond, a difference less than 2.1 is a ...
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Hydrogen halide acidity

Why is it that $$\mathrm{p}K_\mathrm{a}(\ce{HF}) < \mathrm{p}K_\mathrm{a}(\ce{HCl}) < \mathrm{p}K_\mathrm{a}(\ce{HBr}) < \mathrm{p}K_\mathrm{a}(\ce{HI}),$$ even though the electronegativity ...
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Why is HCl not considered to have hydrogen bonding?

A molecule that has hydrogen bonding usually follows these two premises. 1.) There is a hydrogen atom involved 2.) Hydrogen must be bonded to a highly electronegative element which are nitrogen ($\ce{...
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Strongest negative inductive effect group between trimethylammonium, ammonium and dimethylsulfonium groups

Which of the following group exerts the strongest -I effect? $\ce{-N(CH3)3+}$ $\ce{-NH3+}$ $\ce{-S(CH3)2+}$ $\ce{-F}$ My idea is that positive species exerts more -I effect than ...
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Inductive effect and hyperconjugation - one elephant, different parts?

Are the inductive effect and hyperconjugation both different ways of looking at the same phenomenon - i.e. methyl groups donate negative charge for example. Inductively we can argue that carbon is of ...
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Why are bonds ionic when the electronegativity difference between bonded atoms is greater than 1.7?

I'm learning about how to recognise whether a bond is ionic or covalent, based on the difference in electronegativity between the two bonding partners, $\Delta \chi$. What I have now is a formula: ...
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Which molecule is more acidic: CHF3 or CHBr3?

I know that fluorine is more electronegative than bromine. However, because of the size of bromine, it is more stable with a negative charge. In the case of $\ce{HF}$ vs. $\ce{HBr}$, to me, $\ce{HBr}$ ...
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What should be the oxidation state of oxygen in HOF (hypofluorous acid)?

What should be the oxidation state of oxygen in $\ce{HOF}$ (hypofluorous acid)? Sources on the internet have confused me. Most state its oxidation state to be 0, while the others state that it is -2 (...
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Why does NF3 have a smaller bond angle than NH3?

I've already read many answers about the reason why $\ce{NF3}$ has a smaller bond angle than $\ce{NH3}$ , but I can't seem to understand them. Here's my understanding of the situation: $\ce{NH3}$: ...
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How fast do electrons move around the nucleus?

Electrons, as we all know, are incredibly small. Smaller things do tend to move faster, right? So exactly how fast considering how small they are? Also, does the electonegativity between two atoms ...
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What is the explanation of the changes in stability going down a group for carbonates, bicarbonates, fluorides, and chlorides?

For carbonates and bicarbonates, I know that stability increases down the group, and for chlorides and fluorides, stability decreases down the group. Why does this happen? Can someone explain this in ...
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Why are noble metals more electronegative then most metals?

I was researching about electronegativity when I looked up what a graph of electronegativity within the periodic table is. And, this appeared. I scanned it, matching up everything I knew about the ...
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Electronegativity in krypton and xenon?

Why do krypton and xenon have high electronegativity? Noble gases are supposed to be "happy" with the amount of electrons they have, because they have 8 valence electrons (thus, most noble gases have ...
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Why does ozone have an electrostatic potential map similar to that of SO2?

This is the electrostatic potential for ozone. This is the electrostatic potential for sulfur dioxide. (Click to enlarge) They look almost exactly the same except one is all oxygen atoms and the ...
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Why are there peaks in electronegativities in d-block elements?

Looking at the Pauling electronegativities in the Periodic Table (below, from ChemWiki): Asides from the overall trend of increasing electronegativity across and up the Periodic Table (towards ...
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Relative strengths of hydrogen bonds

Order of hydrogen bond strength: $\ce{O-H...N}$ > $\ce{O-H...O}$ > $\ce{N-H...N}$ > $\ce{N-H...O}$. Why is that so? According to me $\ce{O-H...O}$ should have the maximum strength while $\ce{...
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Percentage ionic character when electronegativity is given

What is the ionic character of a bond, $\ce{A-B}$, in terms of the electronegativities of $\ce{A}$ and $\ce{B}$ ($\chi_\ce{A}$ and $\chi_\ce{B}$)? I have been taught that the percentage ionic ...
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Does the dipole moment increase or decrease by increasing the bond length?

It is established the dipole moment is a result of multiplication of the magnitude of charges (Q) and the distance between them (r). What I understand is that when an electron and a proton get closer (...
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Is a SR2+ substituent really more electron-withdrawing than NH3+?

As the electronegativity of nitrogen and sulfur are around 3.04 and 2.58, respectively (according to the Pauling scale). So according to that, $\ce{NH3+}$ should pull the electrons more towards it ...
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Scale to be considered for comparing electronegativities of nitrogen and chlorine

The Pauling scale gives the $\chi$ values of $\ce{N}$ and $\ce{Cl}$ to be $3.04$ and $3.16,$ respectively, but the Allen scale gives the $\chi$ values of $\ce{N}$ and $\ce{Cl}$ to be $3.066$ and $2....
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electronegativity and how it relates to bond strength

my question is, if the strength of the bond between two atoms increases as the difference in electronegativity increases as well. so say, a H-F bond would be stronger than a O-H bond. I'm a little ...
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Why a higher s character increases a carbon atom's electronegativity?

To make us understand certain phenomenon like the higher acidity of alkynes than alkanes and alkenes, our teacher told us to learn this as a general rule: Higher s character leads to a more ...
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4 votes
3 answers
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Bond angles in NH3 and NCl3

The bond angle in a molecule is inversely proportional to the electronegativity of the surrounding atom if the central atom is same. This also happens with $\ce{NH3}$ and $\ce{NF3}$, as bond angle in $...
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Inductive effect of phenyl ring

I completely understand how phenyl group 'releases' or 'donates' electron through resonance, but how is that a phenyl group shows a weak -I effect, despite having electrons literally smeared on itself?...
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Which is more electronegative: chlorine or nitrogen? [duplicate]

Why nitrogen is considered to be less electronegative than chlorine. Nitrogen should be more electronegative as I was reading some content about this and I read some reasonable arguments: $\ce{NCl3}$ ...
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Why and when are bonds broken

I am new to chemistry (I have only done a GCSE in it) so forgive me if I am missing something obvious. But I am trying to very roughly simulate some chemical reactions. My background is in Artificial ...
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Why does C=O have a larger dipole moment than C-O?

Why does $\ce{C=O}$ have a larger dipole moment than $\ce{C-O}$? According to me, dipole moment directly depends upon bond length and electronegativity difference. In $\ce{C=O}$ and $\ce{C-O}$, (I ...
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Why does increasing orbital energy mean an electron can be more easily lost?

Why is the higher the orbital energy, the easier the electron lost? Also, if the distance between the electron and nucleus is getting father,the electronegativity is getting weaker, the electron is ...
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Why is zinc more reactive than copper?

In terms of electronegativity, from what I understand electronegativity increases going across the period, so surely this should mean that zinc less readily loses its outer shell electrons than copper?...
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Geometries of SCl2(OCH3)2 and SF2(OCH3)2

I am not able to understand the difference between structure of $\ce{SCl_{2}(OCH_{3})_{2}}$ and $\ce{SF_{2}(OCH_{3})_{2}}$. I am already well versed with Molecular Orbital and VSEPR theories. I found ...
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7 votes
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Allred-Rochow vs Pauling Electronegativity scale

While observing the trends in electronegativity of the elements, I found a discrepancy between Allred-Rochow and Pauling scales. In Pauling's scale, chlorine is the third most electronegative element (...
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7 votes
1 answer
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Why does attractive forces of nucleus increase more than shielding across groups?

When you study the electronegativity of the elements, the general trend is that it rises with increasing group number, and decreasing period. Supposedly this is because the attractive forces of the ...
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3 votes
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Why is a cationic trialkylammonium functional group inductively withdrawing in nature?

The alkyl groups on the nitrogen ion should donate electrons (alkyl groups are electron donating in nature). So, irrespective of the nitrogen ion being a cation (which is an electrophile), the alkyl ...
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Does ionization energy have anything to do with how reactive an element is?

According to my textbook, fluorine has a pretty high (compared to elements like sodium) first ionization energy. But why does it have such a high requirement to ionize? After all, it actively seeks ...
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Effect of Electronegativity on Bond Angles in NH3 and NF3 [duplicate]

I am reading a book: Concise Inorganic Chemistry by J.D.Lee (Fifth Edition) In the chapter-The Covalent Bond, the author says: $\ce{NF3}$ and $\ce{NH3}$ both have structures based on a tetrahedron ...
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11 votes
2 answers
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Does 1-bromo-4-chlorobenzene have a permanent dipole moment?

My first thought was there would be a dipole moment as chlorine and bromine are unequal in electronegativity. I have since looked up the electronegativity of both chlorine and bromine through the ...
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How can I relate the reactivity series to electronegativity and ionization energy?

I am trying to figure out how the reactivity series comes about. My understanding is that elements with a higher electronegativity will be more reactive than elements with a lower electronegativity, ...
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Why is the electronegativity of indium greater than that of thallium?

Why is the electronegativity of indium greater than that of thallium? One possibility which I had assumed was the poor shielding effect by the d and f orbitals which leads to an increase in the ...
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6 votes
1 answer
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Which is more electronegative: hydrogen or astatine?

Which is more electronegative - hydrogen or astatine? I'm a bit confused because my teacher taught me that for an atom to be electronegative it has to be on the top of the periodic table and/or on the ...
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Why is the OO-H dissociation is unlikely for the Caro's Acid?

Let us consider the Caro's Acid: $\mathrm{H_2SO_5 \equiv SO_3H-OOH}$. It is widely known that the hydrogen tied with the $\mathrm{-OO-}$ group is pretty much unlikely to dissociate: $$ \text {...
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In PCl2F3, why are two Cl atoms not on axial position? [duplicate]

According to these sites: Chemistry Help Molbase in $\ce{PCl2F3}$, both $\ce{Cl}$ and one $\ce{F}$ atom are on equatorial position, and other 2 $\ce{F}$ atoms are on axial position as follows: The ...
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Which atom goes in the middle of a lewis dot structure?

I've read online in multiple sites that the least electronegative atom goes in the middle with the exception of H, which always goes on the outside. However, in the molecule NaCN, C is in the middle. ...
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2 votes
1 answer
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Relationship between dipole moment of a molecule and electronegativities of constituent atoms

I want to know if I can calculate the dipole moment of a molecule given the electronegativity values for the atoms comprising it. I think that dipole moments determine the polarity of molecules, so ...
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Li2O + 2KCl =2 LiCl +K2O: Is it a feasible Reaction?

$$\ce{Li2O + 2KCl <=> 2LiCl + K2O}$$ I got this reaction on a test question paper. With three other options, it was asked whether this reaction is feasible or not? I googled it and found the ...
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Why isn't the ionic radius of Mg2+ bigger than F-? [closed]

They will both have the same number of valence electrons, but $\ce{F-}$ is more electronegative. Why is it not the case that $\ce{Mg^2+}$ has a bigger radius than $\ce{F-}$?
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1 vote
1 answer
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Difficulty understanding redox in terms of hydrogen and oxygen transfer?

I have come across 4 ways of defining oxidation: loss of electrons increase in oxidation number gain of oxygen loss of hydrogen From these definitions, I have an idea of what I think 'oxidation' and ...
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